VI ADVERTISEMENT. 



The Second Volume treats entirely of 

 Astronomy ; and the arrangement of the 

 propositions in their natural or logical or- 

 der, has been particularly attended to. The 

 great variety of the subject, or rather, of the 

 aspects under which the subject appears, ren- 

 ders this a matter of some difficulty ; and, 

 accordingly, there are very few, even of the 

 best treatises of Astronomy, in which the 

 arrangement is not obviously defective. The 

 Systeme du Monde of LA PLACE, and the 

 Traite Elementaire of BIOT, are almost the 

 only exceptions to this rule. To both of 

 these I am under great obligations ; to the 

 first in particular, the most valuable and 

 philosophical compend, I believe, which ex- 

 ists at present of any science. 



In Physical Astronomy I have been more 

 full than any where else ; and on the subject 

 of Central Forces, have given all the inves- 

 tigations. 



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The 



